1. Field
One or more example embodiments relate to an apparatus for supporting a curved portion of a pipe, more particularly, to a fastening-type pipe supporting apparatus capable of supporting a curved pipe against loads acting on the curved portion of the pipe via clamps having curved surfaces and being easily attached to and detached from the curved portion of the pipe.
2. Description of the Related Art
In general, pipes having various shapes are used in power plants and other industrial plants. The pipes may include typically straight portions and curved portions and various loads such as pipe weights, thermal expansion loads, vibration loads, earthquake loads, pipe break loads, or impact loads may act thereon. Pipe supporting structures or apparatuses are used to prevent deformation or destruction of piping systems caused by such loads.
Pipe supporting structures or apparatuses may be broadly classified into an attachment-type and a fastening-type. The attachment-type may include parts such as lugs or stanchions directly connected to pipes by a method such as welding, forging, or casting and the fastening-type may include supporting parts connected to pipes using mechanical parts such as clamps, bolts, or pins.
For example, in the case of the attachment-type, an attachment part is directly welded to a pipe, and thus, the attachment part is not separable from the pipe. Thus, when it is required to measure the thickness of a curved portion of a pipe so as to verify the amount of internal corrosion of the pipe, the attachment part welded to the curved portion of the pipe makes it impossible to measure the thickness of the curved portion of the pipe. In addition, the attachment-type has a negative effect on the structural integrity of pipes and requires an additional local stress evaluation because of parts welded to pipes. Thus, the fastening-type is widely used. Compared to the attachment-type apparatuses, the fastening-type pipe supporting apparatuses are easily attached to and detached from pipes, and it is easy to install fastening-type pipe supporting apparatuses on pipes in the field.
Pipe supporting structures or apparatuses are installed on straight portions or curved portions of pipes so as to maintain pipe stresses less than an allowable stress in the process of pipe stress analysis. In general, pipe supporting structures or apparatuses configured to be installed on straight portions of pipes are of the attachment-type or the fastening-type. Various fastening-type pipe supporting apparatuses for straight portions of pipes have been developed. For example, straight portion clamps 10a and 10b shown in FIGS. 1A and 1B are widely used.
However, the development of fastening-type pipe supporting apparatuses for curved portions of pipes is not yet sufficient, and thus only attachment-type pipe supporting structures are used for curved portions of pipes. Referring to FIGS. 2A and 2B, a lug 30 or a stanchion 40 is welded to a curved portion 20 of a pipe. As described above, however, such an attachment-type pipe supporting structure is practically not separable from a pipe after the attachment-type pipe supporting structure is welded to the pipe, and thus, it is practically impossible to measure the thickness of the curved portion of the pipe for verifying internal corrosion at the curved portion of the pipe. In addition, such attachment-type pipe supporting structures have a negative effect on the structural integrity of pipes, and even more, an additional local stress evaluation is required because of parts welded to pipes.
Therefore, in general, pipe supporting structures or apparatuses are installed on straight portions of pipes except for the case in which pipe supporting structures or apparatuses have to be vitally installed on curved portions of pipes to maintain pipe stresses less than an allowable stress. However, if pipe supporting structures or apparatuses are installed on only straight portions of pipes as described above, it is difficult to select optimal positions for supporting loads. For example, even though pipe stress analysis results show that the curved portion of a pipe is the most effective positions for supporting loads, an additional pipe stress analysis has to be performed to select a pipe supporting structure or apparatus installed on the only straight portion of the pipe instead of the curved portion of the pipe. In addition, according to the results of the additional pipe stress analysis, additional supporting structures or apparatuses may be required. That is, because of limitations of the pipe supporting structures or apparatuses for curved portions of pipes, it is difficult to select optimal installation positions for pipe supporting structures or apparatuses.